telling firefox 91 to always accept self signed certificate.

[Tim Woodall <debianuser@woodall.me.uk>]

I have a buster install where firefox-esr has just been updated. I
cannot work out how to tell it to always accept self-signed (and
expired) certificates without a warning.

I had a permanent exception set under about:preferences#privacy
ViewCertificates but that didn't seem to be working. And attempting to
add another exception changed the existing "permanent" exception to
temporary with no option to check the "add permanent exception" box.

I cannot get firefox to use http instead, it insists on changing to
https even though https only mode is turned off (I'm not 100% sure http
will work anyway but firefox won't even try)

I don't care about "security" for this connection. It's an IPMI console
that is only accessible on the same (trusted) physical lan and remote
access is only possible via a vpn.

I cannot find anything in about:config that seems to help this.

Before I downgrade back to the old version of firefox is there anything
I can do so that this "just works" without prompting?

Tim.